1. Field of the Invention
The present invention relates to an optical device and a projection device including a light synthesis device which synthesizes multiple rays of reflected light reflected by multiple polarization elements to be output as one ray of image light.
2. Description of the Related Art
There has been a liquid crystal projector (projection device) including a light source unit configured of a lamp or the like supported by a reflector, an image formation unit configured to form an image, and a projection unit configured of a lens or the like which projects the image. In the image formation unit, a cross-dichroic prism (light synthesis device) which synthesizes multiple rays of reflected light reflected by multiple polarization elements to be output as one ray of image light is arranged.
Each polarization element transmits a polarization component of incident light in a specific direction so as to be incident upon a corresponding reflective liquid crystal panel and reflects each polarization component in a direction according to the rotation of the liquid crystal panel. Then, each polarization element is secured to the cross-dichroic prism each with a separate spacer plate so that respective rays of reflected light are synthesized into one ray of image light.